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You searched for +publisher:"Texas A&M University" +contributor:("Shamberger, Patrick"). Showing records 1 – 3 of 3 total matches.

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Texas A&M University

1. Yegin, Cengiz. Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications.

Degree: PhD, Materials Science and Engineering, 2016, Texas A&M University

The inefficient dissipation of heat is a crucial problem that limits the reliability and performance of all electronic systems. As electronic devices get smaller and more powerful, and moving components of machinery operate at higher speeds, the need for better thermal management strategies is becoming increasingly important. Heat removal during the operation of electronic, electrochemical, and mechanical devices is facilitated by high-performance thermal interface materials (TIMs), which are utilized to couple devices to heat sinks. Herein, we report a new class of TIMs involving the chemical integration of boron nitride nanosheets (BNNS), soft organic linkers, and a metal matrix - which are prepared by chemisorption coupled electrodeposition approach. Thermal and mechanical characterization of the copper-based hybrid nanocomposites involving thiosemicarbazide demonstrates bulk thermal conductivities ranging from 211 to 277 W/(m.K), which are very high considering their relatively low elastic modulus values on the order of 15 to 30 GPa. The synergistic combination of these properties leads to the lowest measured total thermal resistivity to date for a TIM with a typical bondline thickness of 30-50 µm: 0.38 to 0.56 mm2.K/W. Moreover, its coefficient of thermal expansion (CTE) is 11 ppm/K, forming a mediation zone with a low thermally-induced axial stress due to its close proximity to the CTE of most coupling surfaces needing thermal management. Furthermore, preliminary electrochemical tests revealed that the presence of organic ligands and BNNS in the hybrid nanocomposite TIMs improves the corrosion protection behavior of the TIMs by nearly 72%. Further analysis of the hybrid nanocomposite TIMs included the replacement of thiosemicarbazide with various organic ligands and the replacement of copper matrix with silver. Compared to all the ligands that were used in copper-based hybrid nanocomposites, the most promising thermal and mechanical test results were obtained from thiosemicarbazide. On the other hand, the best silver-based nanocomposite TIM was determined to be the one involving the ligand 2-mercapto-5-benzimidazolecarboxylic acid, in which the thermal conductivity was near 360 W/m.K, and elastic modulus and hardness were about 35 GPa and 0.25 GPa, respectively. The promising results indicate that metal-inorganic-organic nanocomposite TIMs can be great alternatives to currently used TIMs in the market. Advisors/Committee Members: Akbulut, Mustafa (advisor), Cheng, Zhengdong (committee member), Ugaz, Victor (committee member), Shamberger, Patrick (committee member).

Subjects/Keywords: Thermal Interface Materials; Ultra Low Thermal Resistance; Enhanced Thermal Conductivity; Mechanically Compliant

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APA (6th Edition):

Yegin, C. (2016). Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/159049

Chicago Manual of Style (16th Edition):

Yegin, Cengiz. “Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications.” 2016. Doctoral Dissertation, Texas A&M University. Accessed February 17, 2019. http://hdl.handle.net/1969.1/159049.

MLA Handbook (7th Edition):

Yegin, Cengiz. “Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications.” 2016. Web. 17 Feb 2019.

Vancouver:

Yegin C. Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications. [Internet] [Doctoral dissertation]. Texas A&M University; 2016. [cited 2019 Feb 17]. Available from: http://hdl.handle.net/1969.1/159049.

Council of Science Editors:

Yegin C. Synthesis, Production and Characterization of Next Generation Thermal Interface Materials for Electronic Applications. [Doctoral Dissertation]. Texas A&M University; 2016. Available from: http://hdl.handle.net/1969.1/159049


Texas A&M University

2. Smith, Taylor William. Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries.

Degree: 2015, Texas A&M University

In attempting to develop energy storage systems possessing superior properties to traditional lithium ion batteries (LIBs), numerous alternative chemistries have undergone study and development. Of these, the lithium-sulfur battery seems one of the more promising contenders for replacing LIBs, particularly for applications like electric vehicles. Nevertheless, a variety of limitations have prevented lithium-sulfur battery introduction to the marketplace, in spite of almost fifty years of research, including polysulfide shuttle, reactivity of the electrolyte, and anodic microstructure evolution. This thesis will explore the use of first-principles computational techniques in understanding the impact of electrolyte composition, polysulfide molecules, and lithium crystal structure on the reactions taking place near the lithium anode in order to better address the problems facing lithium-sulfur batteries. Using ab initio molecular dynamics simulations (AIMD), in conjunction with static density functional theory (DFT) optimizations, Bader charge analysis, and additional analytical techniques, the interactions and impacts of the different components of the typical lithium-sulfur battery can be examined on a molecular basis. It is the author?s hope that a better theoretical understanding of how these species behave will enable design and implementation of real-world lithium-sulfur systems capable of meeting and overcoming the difficulties facing their commercialization. In order to test the effects of lithium crystal structure on electrolyte stability and surface morphology evolution, both a (100) and (110) lithium metal surface were created and tested using AIMD simulations. There was a minimal difference in the results for each structure, in both the surface morphology and ratio of solvent molecules reduced by the lithium. In testing the effects and stability of various solvents, it was found that ethylene carbonate reduced readily, while dioxolane, dimethoxyethane, and fluorinated ether molecules were quite stable in the presence of the anode. AIMD simulations of polysulfide molecules in the vicinity of the lithium surface show high reactivity, as seen experimentally, and subsequent DFT calculations indicate the reduction of long-chain polysulfide molecules in the presence of Li atoms is a thermodynamically favorable reaction pathway. Finally, it was observed that high molarity salt systems have properties capable of improving cell performance. Advisors/Committee Members: Balbuena, Perla B (advisor), Mukherjee, Partha P (committee member), Shamberger, Patrick J (committee member).

Subjects/Keywords: Batteries; Lithium-Sulfur; Simulations; Polysulfide Shuttle; Battery Anode; Molecular Dynamics

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Smith, T. W. (2015). Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/156452

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Smith, Taylor William. “Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries.” 2015. Thesis, Texas A&M University. Accessed February 17, 2019. http://hdl.handle.net/1969.1/156452.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Smith, Taylor William. “Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries.” 2015. Web. 17 Feb 2019.

Vancouver:

Smith TW. Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries. [Internet] [Thesis]. Texas A&M University; 2015. [cited 2019 Feb 17]. Available from: http://hdl.handle.net/1969.1/156452.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Smith TW. Effects of Electrolyte Composition and Polysulfide Species on the Reactivity of Lithium Anodes in Lithium-Sulfur Batteries. [Thesis]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/156452

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Texas A&M University

3. Evans, Jordan Andrew. Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage.

Degree: PhD, Materials Science and Engineering, 2017, Texas A&M University

The impact of radiation-induced effects on the properties of alloys fabricated using additive manufacturing (AM) was evaluated through the implementation of ion beam irradiation testing followed by electron backscatter diffraction (EBSD), scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS), nanoindentation, scanning probe microscopy (SPM), and transmission electron microscopy (TEM). Inconel 600 (I600) and 316L stainless steel (316L) rods were fabricated by Quad City Manufacturing Laboratory in collaboration with Lockheed Martin for this study. The rods were produced in three distinct orientations (vertical, horizontal, and 45°) using laser additive manufacturing (LAM). Conventionally manufactured I600 and 316L rods were purchased from Metal Samples, Inc. to enable comparative studies. The I600 and 316L LAM specimens were heat treated to 900 °C and 650 °C in argon with no cold working, respectively. Similarly, the conventionally manufactured I600 and 316L control specimens were cold rolled and annealed at 980 °C and 1040 °C in argon with no cold working, respectively. XRD of unirradiated specimens showed differences in peak ratios between build orientations, indicating anisotropic grain structures for samples fabricated by LAM. All LAM rods contained significantly fewer coincidence site lattice (CSL) boundaries and more residual strain compared to the controls before and after irradiation, regardless of build direction, as determined by EBSD. Material performance parameters such as resistance to radiation-enhanced embrittlement, corrosion, creep, intergranular stress corrosion cracking, and hydrogen-induced cracking were inferred from CSL theory, which suggests that all LAM rods are more susceptible to grain boundary-related failure mechanisms than their conventionally manufactured counterparts. All alloys built by LAM are strongly textured with parallel to the build direction before and after irradiation. Directionally dependent Taylor Factor distributions suggest that resistance to slip depends on build direction where, from highest to lowest resistance: horizontal > 45° > vertical. All I600 samples experienced radiation-induced segregation which, according to SEM/EDS and SPM studies, resulted in the formation of chromium carbide precipitates on to the irradiated surfaces. Strong anisotropic mechanical behavior was observed in the LAM rods, as measured by nanoindentation and bulk tensile testing. The hardness of the unirradiated as-annealed specimens, from greatest to least, is: horizontal > 45° > vertical. The radiation-induced hardening of LAM specimens, from greatest to least, is: horizontal > 45° > vertical. The orientation dependence of radiation-induced segregation and hardening mechanisms is discussed. The ultimate outcome of this work is a first-of-a-kind high-dose radiation damage study of alloys fabricated by LAM, revealing that the radiation-induced changes in material properties for these alloys is dependent upon build orientation. Advisors/Committee Members: McDeavitt, Sean (advisor), Perez-Nunez, Delia (committee member), Shao, Lin (committee member), Shamberger, Patrick (committee member), Tsvetkov, Pavel (committee member).

Subjects/Keywords: additive manufacturing; radiation damage; anisotropy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Evans, J. A. (2017). Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/169649

Chicago Manual of Style (16th Edition):

Evans, Jordan Andrew. “Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage.” 2017. Doctoral Dissertation, Texas A&M University. Accessed February 17, 2019. http://hdl.handle.net/1969.1/169649.

MLA Handbook (7th Edition):

Evans, Jordan Andrew. “Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage.” 2017. Web. 17 Feb 2019.

Vancouver:

Evans JA. Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage. [Internet] [Doctoral dissertation]. Texas A&M University; 2017. [cited 2019 Feb 17]. Available from: http://hdl.handle.net/1969.1/169649.

Council of Science Editors:

Evans JA. Anisotropic Response of Laser Additively Manufactured Nuclear Alloys to Radiation Damage. [Doctoral Dissertation]. Texas A&M University; 2017. Available from: http://hdl.handle.net/1969.1/169649

.